1. Field of the Invention
The invention relates to a reset system, a mobile device, a communication device and a reset method, and, more specifically, to a reset system, a mobile device, a communication device and a reset method for a tire pressure measuring system equipped for a mobile unit, such as a vehicle.
2. Description of the Related Art
A recent mobile unit (for example, a vehicle) is equipped with a tire pressure monitoring system (TPMS). The TPMS measures the air pressure of a tire provided for the mobile unit, and performs operation, such as warning, when the measured air pressure is lower than or equal to a threshold. In the TPMS, an air pressure selected by a driver is set as a normal value, and a reference value determined on the basis of the normal value is prestored. Then, for example, the TPMS performs operation, such as warning, when the measured value indicates an abnormal value that is lower than or equal to the reference value.
When the timing at which a reference value is stored is, for example, set at the time immediately after pumping air again to the tire or at the time of tire replacement, a reference value appropriate to a selected normal value may be stored. Japanese Patent Application Publication No. 7-186642 (JP-A-7-186642) describes a tire pressure abnormality warning system as an example of a technique for storing the reference value. In JP-A-7-186642, for example, a reference value is stored when the system receives an instruction for storing a reference value from a user. In addition, in this example, a switch for giving an instruction for storing a reference value is provided near a tire wheel, and a worker who replaces a tire depresses the switch at the time of tire replacement to store the air pressure at the time of tire replacement as a reference value.
However, the technique described in JP-A-7-186642 has the following problem. That is, in JP-A-7-186642, the switch by which a worker or a user gives an instruction for storing a reference value to the tire pressure abnormality warning system is installed at a portion adjacent to each tire on the back side of a vehicle body. In order to install the switch for giving an initializing instruction on the back side of the, vehicle body, it is necessary to provide space for wires that connect each switch to the tire pressure abnormality warning system, space for installing the switches, and the like. This reduces the flexibility of design.